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How come you can add salt to flour before the yeast?

November 7, 2012 - 8:58am

giyad

How come you can add salt to flour before the yeast?

Sorry I'm sure this has been asked before but I can't seem to find the answer. I don't understand how, if salt kills yeast, we can add salt to the flour before adding the activated yeast? In most pizza recipes that I see you add flour to a bowl and add the salt. Then you take the yeast, water and oil and mix them in another cup. After a couple of minutes you add the yeast mixture to the bowl with the flour and salt.

If the salt is already in there, won't it kill the yeast or is it once the yeast is activated we can do anything we want with the salt?

Salt kills the yeast by dehydration when in direct contact. If you dissolve salt in water the osmotic pressure will be inversely proportional to concentration, thus more water->less osmotic pressure->less (or no) damage for the yeast. Notice that the same reasoning applies with sugar and anything that dissolves in water, what changes is only the solubility.

So should I also not mix the dry yeast and sugar together before adding water? What I usually do is just throw them together in a bowl and then add the water, I'm not sure if I kill any of the yeast though that way, didn't think I could with sugar but I just learned that its the same with salt and sugar for yeast

If your yeast and sugar are poured into a bowl together and water added immediately and you mix it until the yeast and sugar dissolves you're not going to have any great adverse affect on your yeast. It would be preferrable to disolve the yeast in water and then add the sugar but it's not all that critical; don't worry about it.

watch the effect. Sprinkle a spoon of crystal sugar onto the block of fresh yeast and wait a few minutes. Squishing the sugar into the yeast with a fork speeds up the process. Water will be pulled to the surface of the yeast and it will literally turn to liquid as you watch. It will not kill the yeast if liquids are added right away. The liquid yeast blends in very quickly with water and water is reabsorbed into the yeast.

Don't try this with salt though the effect is the same, water is pulled from the yeast cells in a dramatic way. Or better yet, try it... If you have access to lots of fresh yeast (or any kind of yeast) like I do at the moment.

Try an experiment:

Take four 5g blocks of fresh yeast and drop into 4 identical tall and narrow glasses and label.

glass #1 do nothing (control)

glass #2 cover in 5g of sugar

glass #3 cover with 2gm salt (2%)

glass #4 100ml water then drop in 5g sugar and 2g salt and Stir to dissolve crystals. Mark the level with either a rubber band, marker or piece of tape.

Now wait 10 minutes and add 100ml water to the first 3 glasses ((when repeating the experiment, vary/increase the waiting time to hopefully damage yeast cells, compare!))

Then add to #2 2g of salt and add to #3 5g sugar so the last three glasses contain the same amount of water, yeast, sugar and salt. Stir with separate spoons and mark the levels. Observe. Watch and mark at 15 minute intervals. Compare activity or lack thereof. Be sure to look at the sides of the glass for bubbles and the top foam on the surface. How did the yeast dissove, evenly? any separation with time? After a few hours of observing, let them stand without stirring overnight and compare. you can even add flour to all 4 glasses a day later and compare yeast activity. Get to know your yeasty beasties!

To experiment with instant or active dry yeast some moisture needs to be added to the dry yeast in the beginning so add 5g water (one teaspoon) so some kind of reaction can take place, use half a tsp of yeast. have fun! :)

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